Effect of the strain rate on the low cycle fatigue behavior of a 10Cr-2W-Mo-3Co-NbV steel at room temperature

Abstract

The effect of a strain rate varying from ∼10−3 to ∼10−5 s−1 at a strain amplitude ranging from ±0.25% to ±0.6% on the low cycle fatigue (LCF) behavior and the microstructure of a 10%Cr-2%W-0.7%Mo-3%Co-NbV steel with 0.008 wt.% B and 0.003 wt.% N additions was studied at room temperature. The number of cycles to failure tends to slightly increase with decreasing the strain rate. The fatigue lifetime curves at all tested strain rates and strain amplitudes could be described using the Basquin-Manson-Coffin relationship. The transition life of 2Nt, when plastic and elastic strain components are equal, shifted to higher reversals with a decrease in the strain rate from ∼10−3 to ∼10−4 and ∼10−5 s−1, whereas the transition total strain amplitude, when plastic and elastic strain components are equal, remained unchanged. It was found that despite the weak influence of strain rate on the lifetime and microhardness, a decrease in the strain rate facilitates the knitting reaction.